Merge pull request #60304 from hyp/eng/generic-trait-move-hdr

[interop][SwiftToCxx] NFC, move generic traits declarations to shims …

Author: hyp

lib/PrintAsClang/PrintSwiftToClangCoreScaffold.cpp

@@ -210,13 +210,6 @@ void printCxxNaiveException(raw_ostream &os) {
   os << "};\n";
 }
 
-void printGenericTypeTraits(raw_ostream &os) {
-  os << "template<class T>\n";
-  os << "static inline const constexpr bool isUsableInGenericContext = "
-        "false;\n\n";
-  os << "template<class T> inline void * _Nonnull getTypeMetadata();\n\n";
-}
-
 void printPrimitiveGenericTypeTraits(raw_ostream &os, ASTContext &astContext,
                                      PrimitiveTypeMapping &typeMapping,
                                      bool isCForwardDefinition) {
@@ -287,7 +280,6 @@ void swift::printSwiftToClangCoreScaffold(SwiftToClangInteropContext &ctx,
     // C++ only supports inline variables from C++17.
     // FIXME: silence the warning instead?
     os << "#if __cplusplus > 201402L\n";
-    printGenericTypeTraits(os);
     printPrimitiveGenericTypeTraits(os, astContext, typeMapping,
                                     /*isCForwardDefinition=*/false);
     os << "#endif\n";

stdlib/public/SwiftShims/_SwiftCxxInteroperability.h

@@ -50,6 +50,20 @@ inline void opaqueFree(void *_Nonnull p) noexcept {
 }
 
 } // namespace _impl
+
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wc++17-extensions"
+
+/// True if the given type is a Swift type that can be used in a generic context
+/// in Swift.
+template <class T>
+static inline const constexpr bool isUsableInGenericContext = false;
+
+#pragma clang diagnostic pop
+
+/// Returns the type metadat for the given Swift type T.
+template <class T> inline void *_Nonnull getTypeMetadata();
+
 } // namespace swift
 #endif
 

test/Interop/SwiftToCxx/core/swift-impl-defs-in-cxx.swift

@@ -129,11 +129,6 @@
 // CHECK-EMPTY:
 // CHECK-EMPTY:
 // CHECK-NEXT: #if __cplusplus > 201402L
-// CHECK-NEXT: template<class T>
-// CHECK-NEXT: static inline const constexpr bool isUsableInGenericContext = false;
-// CHECK-EMPTY:
-// CHECK-NEXT: template<class T> inline void * _Nonnull getTypeMetadata();
-// CHECK-EMPTY:
 // CHECK-NEXT: template<>
 // CHECK-NEXT: static inline const constexpr bool isUsableInGenericContext<bool> = true;
 // CHECK-EMPTY: